Q71 2020, Time and Work

A person X can complete 20% of work in 8 days and another person Y can complete 25% of the same work in 6 days. If they work together, in how many days will 40% of the work be completed?

एक व्यक्ति X किसी कार्य का 20%, 8 दिनों में पूरा कर सकता है और दूसरा व्यक्ति Y उसी कार्य का 25%, 6 दिनों में पूरा कर सकता है। यदि वे दोनों साथ-साथ काम करते हैं, तो उस कार्य का 40% कितने दिनों में पूरा हो जाएगा?

X can complete 20% of work in 8 days.

So, he will complete 100% work in 40 days.

Similarly, Y can complete 25% of work in 6 days.

So, he will complete 100% work in 24 days.

In 1 day the amount of work they will complete while working together = 1/40 + 1/24 = (3 + 5)/120 = 8/120 = 1/15

So, they need 15 days to complete the whole work.

Hence, the time needed to complete 40% of the work = 40% of 15 = 6 days